Allergic asthma is the most common chronic disease of childhood in the United States. Asthma is also the number one cause of school absences in America. The role of indoor allergen exposure in homes and asthma development and morbidity has been extensively studied. Because children spend a significant amount of time in school, the school classroom environment may be as significant a source of allergen exposure and consequent asthma morbidity as allergen exposure in the home. However, little is known about the role of allergen exposure in schools and asthma morbidity. We hypothesize that exposure to common indoor allergens in the classroom will increase the risk of asthma morbidity in inner-city children with asthma, even after controlling for home allergen exposures. In a longitudinal study of 600 elementary school-aged children with asthma from multiple classrooms in 25 Boston inner-city schools, we will examine the following specific aims: 1) to test whether elevated levels of allergens in the classroom increase the risk of asthma morbidity, even after controlling for allergen exposure in the home;and 2) to test whether the risk of increased asthma morbidity in relation to elevated classroom levels of a specific allergen will be highest for those specifically sensitized to that allergen. An understanding of exposure risk factors specific to the school classroom is critical, because the school classroom environment could potentially be considered as an effective target for prevention of inner-city asthma morbidity by reducing exposures to many symptomatic children through school- based interventions. While the potential importance of the classroom environment to the health of asthmatic children has been recognized nationally, study of this area has lacking. This unique application will build on significant collaborations between the Channing Laboratory at the Brigham and Women's Hospital, Children's Hospital Boston, the Harvard School of Public Health, the University of Massachusetts Amherst, and the Boston Public School System. Our multidisciplinary research group has significant expertise in asthma epidemiology and environmental epidemiology (Drs. Phipatanakul and Gold), environmental assessment (Drs. Phipatanakul, Gold, Muilenberg, and Rogers), and statistics (Drs. Ryan, Hoffman, and Sankaranarayanan [Subramanian]). In addition to its public health relevance, this proposal will recruit a unique school pediatric cohort that will facilitate future hypothesis testing. PUBLIC HEALTH RELEVANCE: Asthma is a disease that affects more than 12% of Americans under the age of 18 for over 14 million missed school days per year, and is the number one cause of school absences in America. Elementary school children spend 6 to 10 hours a day in school, and most of that time is spent in one classroom. The goals of this project are to provide an understanding of exposure risk factors specific to the classroom. This is critical, because the classroom environment could potentially be considered as an effective target for prevention of inner-city asthma morbidity by reducing exposures to many symptomatic children through an intervention in the school classrooms.